Consumption of cocoa may improve walking performance for patients with peripheral artery disease (PAD), according to the results of a trial.
PAD is an abnormal narrowing of arteries other than those that supply the heart or brain. It most commonly affects the legs. Symptoms include pain, tightness, cramping, weakness or other discomfort in the leg muscles while walking.
PAD becomes more common as people age, and in 2015 about 155 million people worldwide suffered from the condition.
In a study published by the American Heart Association, 44 PAD patients aged 60 and over were studied.
Those who drank a beverage containing flavanol-rich cocoa three times a day for six months were able to walk up to 42.6 metres further in a six-minute walking test, compared with those who drank the same number and type of beverages without cocoa.
Those who drank the flavanol-rich cocoa also had improved blood flow to their calves and some improved muscle function compared to the placebo group.
“Few therapies are available for improving walking performance in people with PAD,” said lead study author Mary McDermott from Northwestern University in Chicago.
“In addition to reduced blood flow to the legs, people with peripheral artery disease have been shown to have damaged mitochondria in their calf muscles, perhaps caused by the reduced blood flow. Mitochondria are known as the powerhouse of the cell, converting food to energy.
“Previous research has shown that better mitochondrial health and activity are associated with better walking performance and improving the health of damaged mitochondria could lead to walking improvements.”
Researchers hypothesised that epicatechin, a major flavanol component of cocoa, may increase mitochondrial activity and muscle health in the calves of patients with lower extremity peripheral artery disease, potentially improving patient walking ability.
Epicatechins and flavanols also have the potential to improve blood flow.
Study participants were randomly assigned to drink milk or water mixed with the contents of a powder packet containing flavanol-rich cocoa (15g of cocoa and 75mg of epicatechin daily) or a placebo powder packet without cocoa or epicatechin three times daily over six months.
Walking performance was measured at the beginning of the study and at six months, with a six-minute walk measured 2.5 hours after drinking the beverage and 24 hours after drinking the beverage.
Participants were also given a treadmill walking test and had the blood flow to their legs measured using magnetic resonance imaging (MRI). Participants who consented had a calf muscle biopsy to evaluate muscle health.
The cocoa used in the study is commonly available natural unsweetened cocoa powder, which is rich in the flavanol epicatechin and is found in larger quantities in dark chocolate than in milk chocolate. Regular chocolate would not be expected to have the same effect.
Researchers found that the patients who consumed cocoa showed significant improvement – walking an average of almost 43 metres further in the six-minute walking test compared to their baseline results during the test performed at 2.5 hours after the final study beverage.
Researchers also found increased mitochondrial activity, increased capillary density and other improvements to muscle health in those who consumed the cocoa.
Patients who drank the placebo beverage had a decline of 24.2 metres in their walking distance at 2.5 hours after the final study beverage compared to their baseline results. This is consistent with other studies, in which people with PAD without treatment show declines in their six-minute walk distance over time.
“While we expected the improvements in walking, we were particularly pleased to see that cocoa treatment was also associated with increased capillary density, limb perfusion, mitochondrial activity and an additional measure of overall skeletal muscle health,” Ms McDermott said.
“If our results are confirmed in a larger trial, these findings suggest that cocoa, a relatively inexpensive, safe and accessible product, could potentially produce significant improvements in calf muscle health, blood flow and walking performance for PAD patients.”
Do you suffer from PAD? Have you experienced pain while walking? Do you drink cocoa? Would you consider it after reading the results from this test? Why not share your thoughts in the comments section below?
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